It is known that vehicle wheels are, generally, made up of a cylindrical metal rim having, at the axial extremities, annular flanges between which is defined a slot-in fitting channel for an elastic tyre, the side portions of which, so-called “beads” are blocked up firmly against the annular flanges themselves.
The need is also known to carry out frequent balancing operations which consist in fitting weights, made of lead or other material, at predetermined points of the wheel and along the rim.
During wheel rotation, the fitting of the weights offsets the presence of any tyre and/or rim irregularities.
To carry out such operations, balancing machines are commonly used that comprise a supporting structure for wheel gripping and rotation means, of the type of a horizontal shaft that can be turned axially by means of the operation of motor means and on which the wheel rim is keyed.
The measurement of wheel unbalance is determined during rotation by means of suitable electronic or electro-mechanical devices, such as force transducers fitted along the horizontal shaft.
To the unbalance measurement are normally added other characteristic measurements, such as wheel roundness measurement, wheel eccentricity, amount of tread wear, etc., normally made by means of suitable measuring sensors with or without contact (e.g., feelers or optic sensors). Known balancing machines are shown in U.S. Patent Application Publication No. 2007/0069571, published Mar. 29, 2007, U.S. Patent Application Publication No. 2008/0053223, published Mar. 6, 2008, and U.S. Patent Application Publication No. 2009/0145221, published Jun. 11, 2009.
It is also known that such balancing machines have suitable interface means suitable for allowing interaction with the machine by an operator during unbalance measuring operations and during the subsequent balancing operations.
Such interface means are linked to the balancing machine electronics and allow the interaction between the operator and the machine control software.
The interface means generally comprise a monitor fixed to the supporting structure of the machine and suitable for displaying information relating to unbalance measurements and information such as to guide the operator during the balancing operations.
The interface means also comprise a keyboard with a plurality of keys that can be used by the operator to modify the measuring settings before determining the unbalance, or to allow the operator to display and manage the collected data, after determining the unbalance.
The use of a keyboard however does not always allow making the measurement settings or displaying the data in a fast and intuitive way.
To overcome such drawback, the use is known of control panels personalised according to the specific operations that can be performed by means of the balancing machine, which have one or more buttons and a touch-screen surface made, for example, using capacitive technology.
By running a finger over the touch-screen surface, the operator can, generally speaking, move among different menus of the machine software application displayed on the monitor screen.
Pressing the buttons, on the other hand, allows selecting the functions inside the menus and starting specific processing or measuring operations.
One known solution, in particular, envisages the presence of a control panel with a touch-screen annular surface.
Running a finger on such annular surface, either clockwise or anticlockwise, results in the scrolling from left to right or from right to left among predefined menus or functions displayed by the software application installed on the balancing machine.
These known balancing machines however are susceptible to upgrading.
In fact, the combined use of the touch-screen surface and of one or more buttons is not always easy and quick.
Furthermore, scrolling among all the available menus and options until the desired selection is made can require a fair amount of time, something that considerably affects the total measurement time of a wheel unbalance and balancing.